出现 2 个代码时，Google Vision 崩溃

Question

我在我的应用程序中使用谷歌视觉来读取条形码和二维码。这很好用，但是当扫描的表面有 2 个代码彼此相邻时它会崩溃，如下图所示。

即使单独扫描代码也能正确扫描代码，也会发生这种情况。有谁知道如何阻止这种情况发生？

这是管理代码扫描活动的代码：

public class ScanningActivity extends AppCompatActivity {

    SurfaceView cameraPreview;
    BarcodeDetector barcodeDetector;
    CameraSource cameraSource;
    final Integer requestCameraPermissionID = 1001;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home_activity_add_scanner);

        final int height = getSurfaceViewHeight();
        final int width = getSurfaceViewWidth();

        cameraPreview = findViewById(R.id.surfaceview_scanner);

        barcodeDetector = new BarcodeDetector.Builder(AddScanningActivity.this)
                .setBarcodeFormats(Barcode.ALL_FORMATS)
                .build();
        cameraSource = new CameraSource.Builder(AddScanningActivity.this, barcodeDetector)
                .setAutoFocusEnabled(true)
                .setRequestedPreviewSize(width, height)
                .build();
        barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
            @Override
            public void release() {

            }

            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                final SparseArray<Barcode> barcodes = detections.getDetectedItems();
                if (barcodes.size() != 0) {
                    Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(VIBRATOR_SERVICE);
                    vibrator.vibrate(100);

                    Handler handler = new Handler(Looper.getMainLooper());
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            cameraSource.release();
                        }
                    });
                }
            }
        });
        cameraPreview.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder surfaceHolder) {
                final Handler handler = new Handler();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                            ActivityCompat.requestPermissions(AddScanningActivity.this,
                                    new String[]{Manifest.permission.CAMERA}, requestCameraPermissionID);
                            return;
                        }
                        try {
                            cameraSource.start(cameraPreview.getHolder());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }, 100);
            }

            @Override
            public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                cameraSource.stop();
            }
        });
    }

    private Integer getSurfaceViewHeight() {
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        Integer screenHeight = size.y;

        Rect rectangle = new Rect();
        Window window = getWindow();
        window.getDecorView().getWindowVisibleDisplayFrame(rectangle);
        final int statusBarHeight = rectangle.top;

        int[] attrs = new int[]{R.attr.actionBarSize};
        TypedArray ta = this.obtainStyledAttributes(attrs);
        final int actionBarHeight = ta.getDimensionPixelSize(0, -1);
        ta.recycle();
        return screenHeight - statusBarHeight - actionBarHeight;
    }

    private Integer getSurfaceViewWidth() {
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        return size.x;
    }
}

Answer 1

问题是在释放 cameraSource 之前第二次调用了 receiveDetections 方法。然后第二次调用，该方法再次尝试释放cameraSource，但是已经不可用了，导致报错。下面是工作代码，它只有一个很小的简单变化，即使用布尔'codeDetected'：

public class AddScanningActivity extends AppCompatActivity {

    SurfaceView cameraPreview;
    BarcodeDetector barcodeDetector;
    CameraSource cameraSource;
    final Integer requestCameraPermissionID = 1001;
    Boolean codeDetected = false;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home_activity_add_scanner);

        final int height = getSurfaceViewHeight();
        final int width = getSurfaceViewWidth();

        cameraPreview = findViewById(R.id.surfaceview_scanner);

        barcodeDetector = new BarcodeDetector.Builder(AddScanningActivity.this)
                .setBarcodeFormats(Barcode.ALL_FORMATS)
                .build();
        cameraSource = new CameraSource.Builder(AddScanningActivity.this, barcodeDetector)
                .setAutoFocusEnabled(true)
                .setRequestedPreviewSize(width, height)
                .build();
        barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
            @Override
            public void release() {

            }

            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                    final SparseArray<Barcode> barcodes = detections.getDetectedItems();
                    if (barcodes.size() != 0 && !codeDetected) {
                        codeDetected = true;
                        Vibrator vibrator = (Vibrator) getApplicationContext().getSystemService(VIBRATOR_SERVICE);
                        vibrator.vibrate(100);

                        Handler handler = new Handler(Looper.getMainLooper());
                        handler.post(new Runnable() {
                            @Override
                            public void run() {
                                cameraSource.release();
                            }
                        });
                    }
            }
        });
        cameraPreview.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder surfaceHolder) {
                final Handler handler = new Handler();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                            ActivityCompat.requestPermissions(AddScanningActivity.this,
                                    new String[]{Manifest.permission.CAMERA}, requestCameraPermissionID);
                            return;
                        }
                        try {
                            cameraSource.start(cameraPreview.getHolder());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }, 100);
            }

            @Override
            public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                cameraSource.stop();
            }
        });
    }

    private Integer getSurfaceViewHeight() {
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        Integer screenHeight = size.y;

        Rect rectangle = new Rect();
        Window window = getWindow();
        window.getDecorView().getWindowVisibleDisplayFrame(rectangle);
        final int statusBarHeight = rectangle.top;

        int[] attrs = new int[] {R.attr.actionBarSize};
        TypedArray ta = this.obtainStyledAttributes(attrs);
        final int actionBarHeight = ta.getDimensionPixelSize(0, -1);
        ta.recycle();
        return screenHeight - statusBarHeight - actionBarHeight;
    }

    private Integer getSurfaceViewWidth() {
        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        return size.x;
    }
}